mtd: nand: pxa3xx: Add a nice comment to pxa3xx_set_datasize()

Add a comment clarifying the use of pxa3xx_set_datasize() which is only
applicable on data read/write commands (i.e. commands with a data cycle,
such as READID, READ0, STATUS, etc.)
Signed-off-by: NEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/pxa3xx_nand.c

@@ -300,6 +300,11 @@ static void pxa3xx_nand_set_timing(struct pxa3xx_nand_host *host,
 	nand_writel(info, NDTR1CS0, ndtr1);
 }
 
+/*
+ * Set the data and OOB size, depending on the selected
+ * spare and ECC configuration.
+ * Only applicable to READ0, READOOB and PAGEPROG commands.
+ */
 static void pxa3xx_set_datasize(struct pxa3xx_nand_info *info)
 {
 	int oob_enable = info->reg_ndcr & NDCR_SPARE_EN;